The present invention relates generally to a method for manufacturing an electrical component and more particularly to a method for attaching connectors to the coatings of foil capacitors which consist of overlapping and alternatingly staggered coatings of metal foils and of thermoplastic plastic foils, with the plastic foils protruding beyond the metal foils. In foil capacitors of the type to which the present invention relates, a bent end of a connecting wire is always pressed into the protruding portion of the plastic foils while being heated. Subsequently, it is conductively connected by means of soldering to the assigned metal foil. The connecting wire with the bent end is always soldered by means of a soldering piece arranged at the bent end of the connecting wire to the outwardly projecting and approximately rectangularly bent end of at least one metal strip which has been inserted and welded to the corresponding metal foil of the coating and wherein the outwardly projecting end of the metal strip is pressed into the protruding plastic foils in accordance with the teachings of German Pat. No. 20 61 505.
In accordance with the method disclosed in said parent patent, for soldering the connecting wires to metal strips which protrude out of the capacitor and which have a bent end, solder is arranged at the respective end of the connecting wire and the solder is, for example, pressed into a ring which is provided at this end. Moreover, in this case, the solder as well as the bent ring are advantageously painted or sprinkled with a fluxing agent. Subsequently, the connecting wires are either successively or simultaneously heated and this may be accomplished, for example, by means of a soldering iron or it may be accomplished by means of a welding mechanism or by induction heating. During the heating or after they have been heated to an appropriate soldering temperature, the rings are subsequently pressed against a respective end of the metal strip in such a way that about one-half of each ring is in contact with the respective end of the metal strip. As soon as a connecting wire has been soldered to the respective metal strip, each connection is pressed while the respective metal strip is further bent in the heated state against the wound capacitor body to such an extent that that portion of the ring which has remained free during the soldering operation and, possibly, also a portion of the respective metal strip, will come into contact with the end or ends of the plastic foil layers which protrude at the end faces of the wound capacitor body thereby melting the plastic foils. This will have the result that the respective connection and the corresponding metal strip are rigidly embedded in the plastic material after the molten plastic has again hardened. Thus, the soldering point between the metal strip and a connection is sufficiently protected and, simultaneously, the mechanical strength of the connection is significantly increased.
Among other advantages, such a contacting method has the significant advantage that the soldering of the connecting wire to a metal strip and the embedding of a connection to a protective plastic layer may be carried out by machinery in a single working step. On the other hand, however, it is also possible that a bad soldering point may be created when the connecting wire is not centrally placed on the bent end of the metal strip. This may lead to total failure of the component or to the formation of a contact where the parts merely rest against each other. Accordingly, delayed failures of the capacitor may occur due to mechanical stress of the connecting wire or due to temperature changes.
The present invention is directed toward the task of developing a process of the type discussed above which enables secure soldering of the connecting wire to the metal strip located in the capacitor winding.